{{note|The ZFS and SPL kernel modules are tied to a specific kernel version. It would not be possible to apply any kernel updates until updated packages are uploaded to AUR or the archzfs repository.}}

+

{{note|The ZFS and SPL (Solaris Porting Layer is a Linux kernel module which provides many of the Solaris kernel APIs) kernel modules are tied to a specific kernel version. It would not be possible to apply any kernel updates until updated packages are uploaded to AUR or the archzfs repository.}}

+

+

Should you wish to update the core/linux package before the AUR/zfs and AUR/spl packages' dependency lists are updated, a possible work-around is to remove (uninstall) spl and zfs packages (the respective modules and file system may stay in-use), update the core/linux package, build + install zfs and spl packages - just do not forget to edit PKGBUILD and correct the core/linux version number in "depends" section to match the updated version). Finally, the system may be rebooted. [ This is only for the situation, when ZFS is not used for root filesystem. ]

===Unofficial repository===

===Unofficial repository===

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Line 26:

{{hc|/etc/pacman.conf|<nowiki>

{{hc|/etc/pacman.conf|<nowiki>

−

[archzfs]

+

[demz-repo-core]

−

Server = http://demizerone.com/$repo/core/$arch</nowiki>

+

Server = http://demizerone.com/$repo/$arch</nowiki>

}}

}}

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{{hc|# /etc/pacman.conf|<nowiki>

{{hc|# /etc/pacman.conf|<nowiki>

−

[archzfs]

+

[demz-repo-testing]

−

Server = http://demizerone.com/$repo/testing/$arch</nowiki>

+

Server = http://demizerone.com/$repo/$arch</nowiki>

}}

}}

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Line 62:

{{hc|/etc/pacman.conf|<nowiki>

{{hc|/etc/pacman.conf|<nowiki>

−

[archzfs]

+

[demz-repo-archiso]

−

Server = http://demizerone.com/$repo/archiso/$arch</nowiki>

+

Server = http://demizerone.com/$repo/$arch</nowiki>

}}

}}

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==Configuration==

==Configuration==

−

ZFS is considered a "zero administration" filesystem by its creators, therefore configuring ZFS is very straight forward. Configuration is done primarily with two commands, {{ic|zfs}} and {{ic|zpool}}.

+

ZFS is considered a "zero administration" filesystem by its creators; therefore, configuring ZFS is very straight forward. Configuration is done primarily with two commands: {{ic|zfs}} and {{ic|zpool}}.

===mkinitramfs hook===

===mkinitramfs hook===

−

If you are using ZFS on your root filesystem, then you will need to add the ZFS hook to [[Mkinitcpio|mkinitcpio.conf]]. If you are not using ZFS for your root filesystem, then you do not need to add the ZFS hook.

+

If you are using ZFS on your root filesystem, then you will need to add the ZFS hook to [[Mkinitcpio|mkinitcpio.conf]]; if you are not using ZFS for your root filesystem, then you do not need to add the ZFS hook.

You will need to change your [[kernel parameters]] to include the dataset you want to boot. You can use <code>zfs=bootfs</code> to use the ZFS bootfs (set via <code>zpool set bootfs=rpool/ROOT/arch rpool</code>) or you can set the [[kernel parameters]] to <code>zfs=<pool>/<dataset></code> to boot directly from a ZFS dataset.

You will need to change your [[kernel parameters]] to include the dataset you want to boot. You can use <code>zfs=bootfs</code> to use the ZFS bootfs (set via <code>zpool set bootfs=rpool/ROOT/arch rpool</code>) or you can set the [[kernel parameters]] to <code>zfs=<pool>/<dataset></code> to boot directly from a ZFS dataset.

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It is important to place this after any hooks which are needed to prepare the drive before it is mounted. For example, if your ZFS volume is encrypted, then you will need to place encrypt before the zfs hook to unlock it first.

It is important to place this after any hooks which are needed to prepare the drive before it is mounted. For example, if your ZFS volume is encrypted, then you will need to place encrypt before the zfs hook to unlock it first.

−

Recreate the ramdisk

+

Recreate the ramdisk:

# mkinitcpio -p linux

# mkinitcpio -p linux

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==Systemd==

==Systemd==

−

Enable the service so it is automatically started at boot time

+

Enable the service so it is automatically started at boot time:

# systemctl enable zfs.service

# systemctl enable zfs.service

−

To manually start the daemon

+

To manually start the daemon:

# systemctl start zfs.service

# systemctl start zfs.service

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It should not have to be stated, but be careful with this command!

It should not have to be stated, but be careful with this command!

−

Once you have the list of drives, it is now time to get the id's of the drives you will be using. The [http://zfsonlinux.org/faq.html#WhatDevNamesShouldIUseWhenCreatingMyPool zfs on linux developers recommend] using device ids when creating ZFS storage pools of less than 10 devices. To find the id's for your device, simply

+

Once you have the list of drives, it is now time to get the id's of the drives you will be using. The [http://zfsonlinux.org/faq.html#WhatDevNamesShouldIUseWhenCreatingMyPool zfs on Linux developers recommend] using device ids when creating ZFS storage pools of less than 10 devices. To find the id's for your device, simply:

Described as "The last word in filesystems" ZFS is stable, fast, secure, and future-proof. Being licensed under the GPL incompatible CDDL, it is not possible for ZFS to be distributed along with the Linux Kernel. This requirement, however, does not prevent a native Linux kernel module from being developed and distributed by a third party, as is the case with zfsonlinux.org (ZOL).

Installation

Building from AUR

Note: The ZFS and SPL (Solaris Porting Layer is a Linux kernel module which provides many of the Solaris kernel APIs) kernel modules are tied to a specific kernel version. It would not be possible to apply any kernel updates until updated packages are uploaded to AUR or the archzfs repository.

Should you wish to update the core/linux package before the AUR/zfs and AUR/spl packages' dependency lists are updated, a possible work-around is to remove (uninstall) spl and zfs packages (the respective modules and file system may stay in-use), update the core/linux package, build + install zfs and spl packages - just do not forget to edit PKGBUILD and correct the core/linux version number in "depends" section to match the updated version). Finally, the system may be rebooted. [ This is only for the situation, when ZFS is not used for root filesystem. ]

Unofficial repository

For fast and effortless installation and updates, the "archzfs" signed repository is available to add to your pacman.conf:

/etc/pacman.conf

[demz-repo-core]
Server = http://demizerone.com/$repo/$arch

The repository and packages are signed with the maintainer's PGP key which is verifiable here: http://demizerone.com. This key is not trusted by any of the Arch Linux master keys, so it will need to be locally signed before use. See pacman-key.

Add the maintainer's key,

# pacman-key -r 0EE7A126

and locally sign to add it to the system's trust database,

# pacman-key --lsign-key 0EE7A126

Once the key has been signed, it is now possible to update the package database,

# pacman -Syy

and install ZFS packages:

# pacman -S archzfs

Archzfs testing repository

If you have the testing repository active in pacman.conf then it is possible to use the archzfs repository that tracks the testing kernel.

# /etc/pacman.conf

[demz-repo-testing]
Server = http://demizerone.com/$repo/$arch

Archiso tracking repository

ZFS can easily be used from within the archiso live environment by using the special archiso tracking repository for ZFS. This repository makes it easy to install Arch Linux on a root ZFS filesystem, or to mount ZFS pools from within an archiso live environment using an up-to-date live medium. To use this repository from the live environment, add the following server line to pacman.conf:

/etc/pacman.conf

[demz-repo-archiso]
Server = http://demizerone.com/$repo/$arch

This repository and packages are also signed, so the key must be locally signed following the steps listed in the previous section before use. For a guide on how to install Arch Linux on to a root ZFS filesystem, see Installing Arch Linux on ZFS.

Configuration

ZFS is considered a "zero administration" filesystem by its creators; therefore, configuring ZFS is very straight forward. Configuration is done primarily with two commands: zfs and zpool.

mkinitramfs hook

If you are using ZFS on your root filesystem, then you will need to add the ZFS hook to mkinitcpio.conf; if you are not using ZFS for your root filesystem, then you do not need to add the ZFS hook.

You will need to change your kernel parameters to include the dataset you want to boot. You can use zfs=bootfs to use the ZFS bootfs (set via zpool set bootfs=rpool/ROOT/arch rpool) or you can set the kernel parameters to zfs=<pool>/<dataset> to boot directly from a ZFS dataset.

To see all available options for the ZFS hook:

$ mkinitcpio -H zfs

To use the mkinitcpio hook, you will need to add zfs to your HOOKS in /etc/mkinitcpio.conf:

Note: It is not necessary to use the "fsck" hook with ZFS. ZFS automatically fixes any errors that occur within the filesystem. However, if the hook is required for another filesystem used on the system, such as ext4, the current ZFS packaging implementation does not yet properly handle fsck requests from mkinitcpio and an error is produced when generating a new ramdisk.

It is important to place this after any hooks which are needed to prepare the drive before it is mounted. For example, if your ZFS volume is encrypted, then you will need to place encrypt before the zfs hook to unlock it first.

Recreate the ramdisk:

# mkinitcpio -p linux

Automatic Start

For ZFS to live by its "zero administration" namesake, the zfs daemon must be loaded at startup. A benefit to this is that it is not necessary to mount your zpool in /etc/fstab; the zfs daemon imports and mounts one zfs pool automatically. The daemon mounts a zfs pool reading the file /etc/zfs/zpool.cache, so the zfs pool that you want to automatically mounted must write the file there.

Set a pool as to be automatically mounted by the zfs daemon:

# zpool set cachefile=/etc/zfs/zpool.cache <pool>

Systemd

Enable the service so it is automatically started at boot time:

# systemctl enable zfs.service

To manually start the daemon:

# systemctl start zfs.service

Create a storage pool

Use # parted --list to see a list of all available drives. It is not necessary to partition your drives before creating the zfs filesystem, this will be done automatically. However, if you feel the need to completely wipe your drive before creating the filesystem, this can be easily done with the dd command.

# dd if=/dev/zero of=/dev/<device>

It should not have to be stated, but be careful with this command!

Once you have the list of drives, it is now time to get the id's of the drives you will be using. The zfs on Linux developers recommend using device ids when creating ZFS storage pools of less than 10 devices. To find the id's for your device, simply:

Export a storage pool

Swap partition

ZFS does not allow to use swapfiles, but you can use a ZFS volume as swap partition. It is importart to set the ZVOL block size to match the system page size, for x86_64 systems that is 4k.

Create a 8gb zfs volume:

# zfs create -V 8gb -b 4K <pool>/swap

Prepare it as swap partition:

# mkswap /dev/zvol/<pool>/maindisk/swap

Enable swap:

# swapon /dev/zvol/<pool>/maindisk/swap

To make it permament you need to edit your /etc/fstab.

Add a line to /etc/fstab:

/dev/zvol/<pool>/swap none swap defaults 0 0

Troubleshooting

does not contain an EFI label

The following error will occur when attempting to create a zfs filesystem,

/dev/disk/by-id/<id> does not contain an EFI label but it may contain partition

The way to overcome this is to use -f with the zfs create command.

No hostid found

An error that occurs at boot with the following lines appearing before initscript output:

ZFS: No hostid found on kernel command line or /etc/hostid.

This warning occurs because the ZFS module does not have access to the spl hosted. There are two solutions, for this. You can either place your spl hostid in the kernel parameters in your boot loader. For example, adding spl.spl_hostid=0x00bab10c.

The other solution is to make sure that there is a hostid in /etc/hostid, and then regenerate the initramfs image. Which will copy the hostid into the initramfs image.

# mkinitcpio -p linux

On boot the zfs pool does not mount stating: "pool may be in use from other system"

You can always ignore the check adding zfs_force=1 in your kernel parameters, but it is not advisable as a permanent solution.

First of all double check you actually exported the pool correctly. Exporting the zpool clears the hostid marking the ownership. So during the first boot the zpool should mount correctly. If it does not there is some other problem.

Reboot again, if the zfs pool refuses to mount it means your hostid is not yet correctly set in the early boot phase and it confuses zfs. So you have to manually tell zfs the correct number, once the hostid is coherent across the reboots the zpool will mount correctly.

Boot using zfs_force and write down your hostid. This one is just an example.

% hostid
0a0af0f8

Follow the previous section to set it.

Tips and tricks

Emergency chroot repair with archzfs

Here is how to use the archiso to get into your ZFS filesystem for maintenance.

Boot the latest archiso and bring up your network:

# wifi-menu
# ip link set eth0 up

Test the network connection:

# ping google.com

Sync the pacman package database:

# pacman -Syy

(optional) Install your favorite text editor:

# pacman -S vim

Add archzfs archiso repository to pacman.conf:

/etc/pacman.conf

[demz-repo-archiso]
Server = http://demizerone.com/$repo/$arch

Sync the pacman package database:

# pacman -Syy

Install the ZFS package group:

# pacman -S archzfs

Load the ZFS kernel modules:

# modprobe zfs

Import your pool:

# zpool import -a -R /mnt

Mount your boot partitions (if you have them):

# mount /dev/sda2 /mnt/boot
# mount /dev/sda1 /mnt/boot/efi

Chroot into your ZFS filesystem:

# arch-chroot /mnt /bin/bash

Check your kernel version:

# pacman -Qi linux
# uname -r

uname will show the kernel version of the archiso. If they are different, you will need to run depmod (in the chroot) with the correct kernel version of your chroot installation:

# depmod -a 3.6.9-1-ARCH (version gathered from pacman -Qi linux)

This will load the correct kernel modules for the kernel version installed in your chroot installation.